<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="UTF-8" />
		<meta http-equiv="X-UA-Compatible" content="IE=edge" />
		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
		<title>Document</title>
		<style>
			body {
				margin: 0;
				padding: 0;
			}
			.container {
				/* width: 300px; */
				height: 300px;
				background-color: #0f0;
			}
			.box {
				width: 100px;
				height: 100px;
				background-color: #f00;
				margin: 0 auto;
			}
		</style>
	</head>
	<body>
		<div class="container">
			<div class="box"></div>
		</div>
	</body>
</html>
